1. Field
The invention relates to a radiator fan control for heat pump HVAC. More particularly, the invention relates to a radiator fan control for heat pump HVAC which can selectively reverse fan direction based on ambient temperature and reduce ice buildup on a liquid-gas converter.
2. Background
Traditionally, automobiles utilize heat from an internal combustion engine to warm air that is to be distributed into a passenger area of an automobile. In automobiles with high technology energy use such as fuel cells, an engine in the automobile may be relatively efficient such that it does not generate sufficient heat to warm the passengers of the automobile. Thus, an HVAC system may need to include an active heating system to generate heat to distribute to passengers in the automobile.
However, an HVAC system that actively generates heat generally absorbs energy from the ambient air to the automobile to produce the heat. This can be problematic when there is a low temperature in the ambient air because it is difficult to extract energy from ambient air with low energy. Furthermore, the absorption of energy can cause ice to build up on the HVAC system, particularly on the components that are absorbing energy from the ambient air. This is also problematic because the ice build up can also make it more difficult to absorb energy from the ambient air to convert to heat for the passengers.
The ice build up can also be accelerated if there is high moisture content in the air, such as when there is rain, fog, snow, or a relatively high humidity. Furthermore, if the automobile is moving forward, for example, the rain, fog, snow, or air with a relatively high humidity could be forced onto the automobile. This problem is also exacerbated if the automobile is moving at a relatively fast speed as more rain, fog, snow, or air with a relatively high humidity strikes the automobile. Thus, considerable energy must be expended by the HVAC system to generate the heat for the passengers as it seeks to absorb energy from the ambient air with low temperature and/or high humidity (i.e., moisture content).
Therefore, a need exists in the art for a HVAC system which can reduce ice build up on components of the HVAC system and which has an improved efficiency.